X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=02810b78490093f1f14f7c220897f2661f4bc63f;hp=8192536f38990d04217c1b6a918b9bf27d516189;hb=ea4e22be1da1ccbf316d27f2eb3b14d0e13388e4;hpb=76caef8ba1fb4ca0520a8e2b42815d626484e93c

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 8192536f..02810b78 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -150,6 +150,8 @@ namespace {
 
   #undef S
 
+  const Score BishopPinBonus = make_score(66, 11);
+
   // Bonus for having the side to move (modified by Joona Kiiski)
   const Score Tempo = make_score(24, 11);
 
@@ -577,22 +579,15 @@ Value do_evaluate(const Position& pos, Value& margin) {
 
         mobility += MobilityBonus[Piece][mob];
 
-        // Add a bonus if a slider is pinning an enemy piece
-        if (   (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
-            && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
-        {
-            b = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
-
-            assert(b);
-
-            if (!more_than_one(b) && (b & pos.pieces(Them)))
-                score += ThreatBonus[Piece][type_of(pos.piece_on(lsb(b)))];
-        }
-
         // Decrease score if we are attacked by an enemy pawn. Remaining part
         // of threat evaluation must be done later when we have full attack info.
         if (ei.attackedBy[Them][PAWN] & s)
             score -= ThreatenedByPawnPenalty[Piece];
+        else if (Piece == BISHOP && (PseudoAttacks[Piece][pos.king_square(Them)] & s)) {
+             const Bitboard between = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
+             if (!more_than_one(between))
+                 score += BishopPinBonus;
+        }
 
         // Bishop and knight outposts squares
         if (    (Piece == BISHOP || Piece == KNIGHT)
@@ -699,8 +694,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
                       & ~ei.attackedBy[Them][0];
 
     if (undefendedMinors)
-        score += more_than_one(undefendedMinors) ? UndefendedMinorPenalty * 2
-                                                 : UndefendedMinorPenalty;
+        score += UndefendedMinorPenalty;
 
     // Enemy pieces not defended by a pawn and under our attack
     weakEnemies =  pos.pieces(Them)